Paint-gun



W. KELLY.

PAINTGUN.

APPLICATION FILED Nov. I, 1920.

Patented Aug. 2, 1921.

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4following is a specification.

UNITED STATES- PflusiuA OFFICE.

WALTER KELLY, O BOSTON, MASSACHUSETTS.

PAINT-GUN.

Application led November 1, 1920. Serial No.

yTo @ZZ who-m t may concern.'

Be it known that I, WALTER KELLY, a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented new and useful Improvements in Paint-Guns, of which the This invention relates to a portable paint gun, adapted to force air and liquid paint in the form of a jet through a delivering orifice, the delivery of paint and air b the device being manually controlled an the device being flexibly connected with sources of supply of paint and compressed air.

One object of the invention is to rovide a paint gun having improved means or controlling the delivery of paint and air, in such manner that Yin starting the operation, the

delivery of the air precedes that of the paint, so that no paint can be` delivered without beingatomized.

Another object is to enable the pressure lof the paint entering the gun to close the paint outlet when the operator desires to sto the operation of the gun.

ther objects ofthe invention will be rendered apparent by the following specification.

Of the accompanying drawings forming a part of this specification,-

-Figure l is a longitudinal section of a paintgun embodying the invention, the gun being closed.

Fig. 2 is a view similar to Fig. 1, parts being broken away, and the prepared for operation.

Fi 3 is a fragmentary sectional view,

gun lbeing partly showing the gun fully prepared for operation.

Fig. 4 is a section on line 4 4 of Fig. 1. Fig.A 5 is a section on line 5-5 of F ig-.; 1.

' y Fig. 6 isa sectional view of the inner tube and itsholder.

Fig. 7 is a sectional view, of an adjunct hereinafter described. 1

The same reference characters indicate the same parts in all of the figures. 1

In the drawings, 12 `represents a tubular barrel having a lateral air inlet 13, a lateral paint inlet 14, and a combined air and paint outlet l5', best shown by Fig. 3, said outlet lbeing surrounded by an annular valve seat 16. 17 repa'esents a longitudinally movable tube withinand coaxial with the barrel, and

Specification of Letters Patent.

Patented Aug. 2, 1921.

provided with an air port 18, adapted to register with the inlet 13, as shown by Fig. 2.

19 represents a nozzle, coaxial with the tube 17, and movable longitudinally on the latter to a 'limited extent, the nozzle and tube being provided with interengaging means permitting a partial endwise movement ofthe tube, while the nozzle remains stationary,4 for a purpose hereinafter described, said means being preferably embodied in slots 20 in the tube, and studs .21

' fixed to the nozzle and entering the slots.

The tube 17 and nozzle 19 form an air conduit, and their external surfaces coperate with lthe vinternal surface of the barrel in forming an annular paint conduit surrounding the air conduit.

One end ofthe nozzle 19 is Contracted and forms an annular valve 22, adapted to bear on the valve seat 16, to prevent the delivery of paint tothe barrel outlet.

23 represents a relatively strong tube-proecting spring engaged with the barrel by eing seated on an abutment formed by the end of a iixed tube guide 24 within the barrel, and engaged with the tube 17 by being seated'on a shoulder or collar 25 fixed tothe tube.

'26 represents a weaker nozzle-projecting spring engaged with the tube 17, by being seated on one end of the latter, and with the nozzle by being seated on the valve portion 22 thereof.

The springs 23 and 26 normally hold the tube 17 with its air port 18 out of registration with the barrel air inlet 13, as shown by'Fig. 1, and the nozzle with its valve portion 22 seated on the barrel' valve seat 16.

The tube 17 is provided with means such as a projecting trigger arm '28, formed on the collar 25, whereby the tube may be manually retracted. The initial retraction of vthe tube does not affect the nozzle 19, the latter remaining in its 'projected position until the port 18 registers with the air inlet 13, and the forward ends of the slots 20 in the tube strike the studs 21 on the nozzle. After this a further retraction of the tube 17 causes the retraction of the nozzle 19, as shown by he initial or independent retraction of the tube causes a delivery of air to the barrel outlet 15, and the retraction of the nozzle separates the nozzle valve 22 from the seat 16, and causes the delivery of paint to the barrel outlet 15. The delivery of the air, therefore, precedes that of the paint, so that no paint can pass unatomized through the outlet 15.

The tube 17 is guided vin its movements by the above-mentioned guide 24, and by another guide 30 constituting a stuffing-box, to prevent paint from passing between the guide 3() and the tube 17.

The nozzle 19 is provided with an enlargement or collar 31, constituting a piston, having a sliding fit on the interior of the barrel, and provided with paint-conducting oriice's 32. The rear edge of the collar or piston 31 constitutes a fac'e against which paint, entering the paint conduit, acts to press the nozzle valve 22l against its seat, when the operator releases the trigger 28.

33 represents an inner tube within and coaxial with the tube 17, and adapted to deliver a jet of air to the Acenter of a jet of atomized paint projected from the outlet 15, as indicated by Fig. 1, where 35 indicates a jet of atomized paint, and 36 indicates a jet of air delivered by the inner tube 33. Said inner tube is supported by a holder 37, which is an externally threaded plug, engaged with an internally threaded portion of the barrel 12, and provided with a milled head 38, whereby it may be rotated to longitudinally adjust the inner tube and vary the relative positions of the delivering end of said tube and the barrel outlet 15. In case paint becomes caked or hardened between the valve portion 22 and seat 16, it may be removed b adjusting the inner tube'rearwardly, t us causn air forced through the inner tube to dislor ge the hardened paint. The inner tube may be secured in any adjusted position by a lock-nut 40, bearing on one end of the barrel. An air passage 41,-in the inner tube 33, receives air from the tube 17.

The barrel 12 is provided with an air-conductor, here shown as an air-conducting hand 42, having an air-receiving conduit portion 43, and an air-delivering conduit portion 44, communicating with the barrel inlet 13, saidportions being separated by a partition 70, in which are air ports or passages 71, surroundedby a seat 72, for a pressure-regulating valve 7 3. Said valve 1s normall pressed toward the seat 72 bya relative y weak spring 74. The valve 'is fixed to la stem 75, which is movable in suitable guides, and projects through the partition 70, and is held'by the spring 74 against a piston 76 of greater area than the valve, and fitted to slide in anadjustable screw-threaded cylinder 77, engaged with an internally threaded socket 7 8, fixed to one wall of the hand grip 42. A spring 79, which is stronger than the spring 74, presses the piston 76 a ainstthe. stem 75, and tends to open the vai-rive 73.' When the pressure of the entering air acting on the piston 76, is suHicient to overcome the sprin 79, the valve 73 is moved toward its seat y the spring 74, and reduces the lpressure of the air passing to the barrel in et 13. When the entering air pressure is decreased, the valve 73 is moved away from its seat by the spring 79 and piston 76. The force and resistance of the sprin 79 may be varied by turning the cylinder 7 in the socket 78, the cylinder being adapted by a slot or opening 80 to be turned and adjusted. An adjustable pressure-regulating means is thus provided, adapted to be adjusted by the operator to compensate for variations of pressure of the air supplied.

The head 38 may be the casing of a pressure gage of any suitable construction, adapted to indicate the pressure of air adf mitted to the inner tube 33. Said gage may include a Bourdon tube 38, conventionally shown by dotted lines in Fig. 6, adapted to be moved in one direction by an increase of Iair pressure, and in the opposite direction by its own resiliency, and a suitable pointer movable by said tube;

Foreign matter such as dust carried by the air entering the hand gri 42, may be arrested by a strainer 81, wliich is preferably a tube of nely perforated sheet metal, or wire gauze, inserted at one end in an orifice in a partition 82,V formed to. cause theY air entering the hand grip through the nipple to pass through the strainer before entering the conduit portion 43. The opposite end of the strainer is inserted in a threaded cap 83, which is screwed into a tapped oriicein one wall of the hand grip, and is removable with the strainer to permit the re- Inoval of foreign matter arrested by the strainer.

To concentrate the jet 35, I provide a mufiier, composed of a casing 56, having anannular inner end 57, attached to the barrel 12, and surrounding the outlet 15, and a conl tracted outer end 58, formed to deliver a concentrated jet. Any paint accumulating in liquid form in the lower portion of the casing 56, enters a stand pipe 59, through an orifice 60. The open upper end .of the stand'pipe is in the path of the jet 35, so that an outward flow of paint entering the stand pipe is induced by the jet, the paint being atomized at the same time.

Fig. 7 shows a tube 62, which mav be substituted for the stand vpipe 59,` and may be connected with a 4source of paint supply. The hand grip 42 has a nip le 65V for engagement wlth' axfiexible, tu e, connected with a source of air supply. The paint inlet 14 is formed as a nipple for engagement with another flexible tube connected with asource of paint supply. The trigger 28 projects beside'the hand grip 42, so that it may be pressed by a linger of the hand grasping the ip. A movement of the trigger toward t e hand grip irst moves the tube 17 to connect the airl ort 18 with the air inlet 13,'as shown by ig. 2, and-thenmoves the nozzle 19 to open the valve 22, as shown by Fig. 3.

Retraction of the nozzle during the initial retraction of the tube 17, and until the for- Wardend of the tube slot 20 engages the nozzle stud 21, is prevented partly by the spring 26, and partly by the pressure of paint against the piston '30. When the operator releases the trigger, the spring 23 pro@ 'jects the tube 17, and the latter acts through vated staging. remote `from said4 source,-

vvhich is usually on the ground or on a floor, is enabled to inspect, control, and ad'ust said means Without leaving his station. he pressure gage 38 attached vto and movable with the gun, enables the operator to ascertain the existing air pressure, and to re ulate` the same, if necessary, Without leaving his station.

I claim:

1. A paint gun comprising a tubular barrel having a lateral air inlet, a lateral paint inlet, and an air and paint outlet, coincid ing with the axis of the barrel, and surrounded by an annular valve seat, a longltudinally movable tube Within and lcoaxial with the barrel, and having an air port adapted to register With the air inlet of the barrel, a nozz e .carried by the tube and having an annular valve adapted to bear on said seat, said tube and nozzle forming an air conduit and cooperating with the barrel in forming an annular paint conduit surrounding the air conduit,said annular valve and annular valve seat being adapted to prevent the delivery of paint to the barrel outlet, a spring which normally projects the tube and barrel to close the tube air port and the nozzle valve, and means for manually retracting the tube and nozzle to open said air port and valve.

2. A paint gun comprising a'tubular barrel havingefa ,lateral air inlet an air-conducting hand 'grip communicating with said inlet, a lateral paint inlet, and an air and paint outlet coinciding With the axis of the barrel, and' a longitudinally movable tubev Within and coaxial With the barrel, and havingan air port adapted to register with the air inlet of the barrel, a nozzle carried by the tube and having an annular valve adapted to bear on sald seat, said tube and nozzle forming an air conduit, and coperating with the barrel in forming an annular paint conduit surrounding fthe air conduit, said annular valve and annular valve seat being adapted to prevent the delivery of paint to the barrel outlet, a' spring which normally projects the tube and barrel to close the tube air port and the nozzle valve, and a trigger arm fixed to said tube and projecting from the barrel beside the hand grip, Whereby the tube and nozzle may be manually retracted..

3. lA paint gun comprising a tubular barrel, having a lateral air inlet, a lateral paint inlet, and an air and paint outlet coincidinfr `with the axis of the barrel and surroundec by an annular valve seat, a longitudinally movable tube Within and coaxial with the barrel, and provided With a port adapted to register Withthe air inlet of the barrel, a nozzle coaxial with the-tube, said tube and nozzle forming an air conduit and coperating with the barrel in forming an annular -paint conduit surrounding the air conduit,

one end of the nozzle forming an annular valve adapted to bear on said annular valve seat to prevent the delivery of paint to the barrel outlet, a relatively strong tube-projecting spring engaged with the barrel and the tube, a weaker nozzlerojecting spring engaged With the tube an with the nozzle, said springs normally holding the tube with its air port out of registration with the barrel air inlet, and the nozzle With its annular valve seated on the barrel valve seat, and means for manually retracting the tube, the tube and nozzle being provided with interengaging means, permitting an initial retraction of the tube alone, and then causing a retraction of the nozzle with the tube, the

said initial retraction registering the tube port with the barrel air inlet, and causing a delivery of air to the barrel outlet, and the retraction of the nozzle separating the nozzle valve from its seat and causing a delivery of paint to said outlet, the delivery of air preceding that of the paint. .Y 4. A paint gun substantially as specified byclaim 1, the said nozzle bein provided, Within the said paint conduit, with a paintconducting piston having a face, against which paint entering the paint conduit acts to press the nozzle valveagainst its seat when the operator releases the tube and nozzle.

5. A paint gun substantially as specified by claim 1, comprising also an inner tube coaxial with said longitudinally movable tube and projecting therefrom to deliver air within a jet of spray issuing fromsaid outlet, said inner tube having an air inlet, receiving air from the longitudinally movable tube'.

6. A paint gun substantially as specified by claim 1, comprising also an inner tube coaxial with said longitudinally movable tube and rojecting therefrom to deliver air within a jet of spray issuing from said outlet, said inner tube having an air inlet, receiving air from thelongitudinally movable tube,l the inner tube and barrel being rovided with means for longitudinally adjust.- ing the inner tube to vary the relative positions of its delivering end and the barrel outlet. i

7. A paint gun substantially as specified by claim 1, comprising also an inner tube coaxial with said longitudinally movable tube and projecting therefrom to deliver air within a jet of spray issuing from said outlet, said inner tube having an air inlet, receiving air from the longitudinally movable tube, the barrel being provided With an internally threaded portion, and the inner tube with an externally threaded holder,l engaging said internally threaded portion, and with a lock-nut adapted to bear on one end of the barrel.

8. A paint gun substantially as specified by claim 1, comprising also an air-conduct ing hand grip, projecting from one side of the barrel, and communicating With the barrel air-inlet, the meansl for manually retracting the longitudinally movable tube being embodied. in a trigger fixed to said tube and projecting beside said hand grip.

9. A paint gun substantially as specified by claim 1, comprising also an air-conducting hand grip, communicating with the air inlet of the barrel, and automatic air-pressure regulating means in said hand grip.

10. A paint gun substantially as specified by claim 1, comprising also an air-conducting hand grip, communicating with the air" inlet of the barrel, and automatic airpressure regulating means in said hand grip, said means being adjustable.

11. A paint gun substantially as specified by claim 1, comprising also an air-conducting hand grip, communicating with the air inlet oi the barrel, air-pressure regulating means in said hand grip, and a pressure gage adapted to indicate the air pressure.

12. A paint gun substantially as specied l )by claim 1, the said barrel being provided with an air-conducting hand-grip, having an air-receivingconduit portion, an air-delivering conduit portion communicating with the air inlet of the barrel, a partition between said conduit portions havingl an air- -is induced by the jet.

conducting passage and a valve seat, a valve in the air-receiving conduit portion controlling the admission of air to said passage', and provided with a spring tending to close vsaid valve, and with a stem projecting into the delivering conduit' portion, a cylinder in the delivering conduit portion, a piston in Said cylinder, and a stronger spring pressin the cylinder against the stem of said vave, said piston being movable `by its spring to openthe valve, and by air pressure in the delivering conduit portion to close the valve. i

13. A paintI gun substantially as specified b claim 12, the saidcylinder being adjustably connected with the hand.grip.

14. A paint gun substantially. as specified by claim 1, said barrel being provided with an air-conducting hand grip, communicating with the air inlet of the barrel, said hand grip having a strainer in the path of air passing through the hand grip to arrest foreign matter carried by the entering air, and means removably connecting the strainer'with the hand grip.v

15. A paint gun comprising a barrel having an outlet, and means for projecting a jet of atomized paint through saidutlet, and a muiiler composed of a casing, having an inner end attached to the barrel and surrounding the outlet, and a contracted outer end formed to concentrate the jet.

1'6. A paintgun substantially as specified by claim 15, the said casing being provided with a stand pipe having a lateral'opening communicating with the lower portion of the casing, and an open end in the path of said jet, the arrangement being such that a iow of paintoutward from the stand pipe 17.. A portable -paint gun comprising a barrel having an air inlet, a paint inlet, an air and paint outlet, and manually controlled means for separately conducting air and paint from said inlets to said outlet, an air conductor attached to and movable With the gun, and communicating with the air inlet of the barrel, and automatic air-pressure regulating means movable With said conductor and gun. j

18. A portable paint gun comprising a barrel having an air inlet, a paint inlet, an air and aint outlet, and manually controlled means or separately conducting air and paint 4from said inletsto said outlet, an air conductor attached to and movable With the gun, and communicating with the air inlet oi the barrel, and automatic air-pressure regulating means in said conductor, said means movable with said` conductor and gun, and having provisions for adjusting said means.

19. A portable paint gun comprising a barrel having an air inlet, a paint inlet, an

air and aint outlet, and manually controlled and gun, and a pressure gage attached to means or separately conducting air and and movable with the gun, and adapted to paint from said inlets to said outlets, an ail` indicate the air pressure. 10 conductor attached to and movable with the In testimony whereof I have aixed my 5 gun, and communicating With the air inlet signatur of the barrel, automatic air pressure-regulating means movable with said conductor WALTER KELLY. 

